CPP water-wave capillary-wave daily-news 人生 the-economist hexo-stellar 诗词 cross product wedge product mathjax latex the-guardian Functional Analysis gravity-capillary-wave exterior algebra 春物 Eulerian and Lagrangian Descriptions Gamma Function Polygamma Fuction Zeta Function Bessel Function dyadic product PINN Gaussian Integral Hankel-Transform Bessel-Function capillary-gravity-wave academic-Eng Fourier-Transform Residue complex-analysis cpp-debug python python-lambda